RU2298024C2 - Colored paint for the stencil printing on the internal side of the pressurized castings - Google Patents

Abstract

FIELD: chemical industry; polygraphy; methods of the stencil printing.

SUBSTANCE: the invention is pertaining to the paint suitable for the stencil printing inside the pressurized castings. The invention describes the paint suitable for the printing films made out of the transparent thermoplastic, consisting predominantly of: a) one or several pigments; b) the binding in the solution in c) the organic solvent or in the mixture of the organic solvents, d) the routine auxiliary materials, if it is desirable, at that as the binding use the copolymer of the poly-(metha)-acrylate containing (м1) from 50 up to 90 % to the mass of alkylmethacrtlate having from 1 up to 6 atoms of carbon in the ethereal radical; (м2) from 5 up to 25 % to the mass, at least, one vinylaromatic compound; (м3) from 1 up to 25 % to the mass of maleic anhydride, and if it is desirable, (м4) from 0 up to 5 % to the mass of the alkylacrylate having from 1 up to 6 atoms of carbon in the ethereal radical or the copolymer of the poly-(metha)-acrylamide containing polymethylmethacrylate with the degree of imidization from 65 up to 80 %, to 1 up to 15 mass % of methacrylic acid and from 1 up to 15 mass % of methacrylic anhydrade. At that the indicated copolymer has the softening temperature by VIKA (ISO 306 B) at least of 115°C. As the dissolvents use aliphatic, cycloaliphatic and aromatic hydrocarbons, ketones, esters, ethers, alcohols, phenoles or their mixtures. The invention also describes the film made out of the thermoplastic printed by the above described paint; the pressurized casting consisting of the film made out of the thermoplastic printed on the opposite side with the above described paint and supplied on this side with the layer of the thermoplastic coating. At that the indicated layer is applied by the operation of pressure die casting on the inside and at that the film and-or the plastic material for operation of the pressure die casting on the inside represents the copolymer of polymethylmethacrylate; and the method of production of the pressurized castings includes the following stages: a) stencil printing of the thermoplastic films by the above described method, b) the film molding, c) the pressurized castings on the inside on the stencil printed film side in the casting mould with the thermoplastic, and d) removal of the pressurized casting from the casting mould. The technical result of the invention: the paint is resistant to the action of the high pressures and temperatures during the operation of the pressurized casting on the inside, the image stencil printed by the paint has the stable color after long-term action of the atmospheric conditions.

EFFECT: the invention ensures, that the paint is resistant to the action of the high pressures and temperatures during the operation of the pressurized casting on the inside, the image stencil printed by the paint has the stable color after the long-term action of the atmospheric conditions.

6 cl, 1 tbl

Description

The invention relates to a paint suitable for printing inside pressed castings, consisting mainly of one or more pigments, optionally ordinary auxiliary substances, and a binder dissolved in an organic solvent or in a mixture of organic solvents.

Screen inks and screen inks are widely used. For example, transparencies can be screen-printed with ink for screen printing. The printed films are then molded and cast on their back in an injection mold (press-fit casting). For example, a wide variety of plastic parts can be produced this way, such as variously printed or colored, replaceable cases for cell phones. The requirements imposed on the quality of screen printing are strict, since in the operation of injection molding from the inside, resistance to temperatures in the region of 260 ° C and pressures of about 1000 bar is required, and there must be no violation with respect to the printed image during the period of use.

German patent application DE 4421561 A1 describes flexible, heat-resistant inks for screen printing. What is disclosed as binders for pigments is thermoplastic aromatic polycarbonates dissolved in common solvents. The use of typical opaque compositions makes it possible to obtain high-contrast printed color models. Conversely, printed color models obtained with a polyacrylate binder are blurry.

It was found that screen printing ink and screen printing ink based on polycarbonate compounds for printing from the back of films that are processed for press-fit castings are not always resistant to the back-side injection molding process in the subsequent injection operation, but also have a greater or lesser tendency to turn yellow after some time and in accordance with the loads on them.

The obvious task is to create an ink suitable for screen printing inside pressed castings, which is relatively stable with respect to the injection molding from the inside out with respect to the images printed by it and which demonstrates extremely high color stability even after prolonged exposure to atmospheric conditions.

This problem is solved by means of ink suitable for printing films made of transparent thermoplastics, especially for printing films used for press-fit castings, consisting mainly of

a) one or more pigments,

b) a binder in solution in

c) an organic solvent or a mixture of organic solvents

d) conventional excipients, if desired,

characterized in that a poly- (meth) -acrylate or poly- (meth) -acrylimide compound is used as a binder, which has a Vika softening point VST (ISO 306 V) of at least 115 ° C.

Paint

Paint consists of

a) one or more pigments, preferably in an amount of from 10 to 50% by weight

b) a binder, preferably in an amount of from 10 to 50% by weight, in solution in

c) an organic solvent or mixture of organic solvents, and

d) if desired, conventional excipients, preferably in an amount up to 10% by weight, in particular from 0.1 to 10% by weight,

wherein all amounts are given relative to liquid paint.

Pigments

The ink contains pigments, preferably in an amount of 10 to 50%, more preferably 15 to 30% by weight relative to the liquid ink.

Examples of suitable pigments include carbon black, titanium dioxide, metallic pigments, red iron oxide or red iron oxide, cobalt pigments, for example, cobalt blue grades, Rinman greens, and organic pigments.

Binder

The paint includes a binder, in particular a polymeric binder, preferably in an amount of from 10 to 50%, in particular from 15 to 35% by weight relative to the liquid paint.

As binders, a poly- (meth) -acrylate or poly- (meth) -acrylimide compound which has a Vicat softening point VST (ISO 306 V) of at least 115 ° C, for example from 115 to 180 °, can be used C, preferably at least 118 ° C, for example, from 118 to 125 ° C, more preferably at least 125 ° C, in particular at least 130 ° C, for example, from 140 to 180 ° C or from 145 to 160 ° C. These binders are very resistant to temperature, as well as to atmospheric conditions and, therefore, are valuable for the properties of the coloring system.

A poly (meth) acrylate compound which is a polymer of

(m1) from 50 to 90% by weight of alkyl methacrylate having from 1 to 6 carbon atoms in the ether radical,

(m2) from 5 to 25% by weight of at least one vinyl aromatic compound,

(m3) from 1 to 25% by weight of maleic anhydride and, if desired,

(m4) from 0 to 5% by weight of alkyl acrylate having from 1 to 6 carbon atoms in the ether radical

Monomers (m1), (m2), (m3) and (m4).

Monomers (m1) used in an amount of 50 to 90% by weight relative to the weight of all monomers are selected from the group of alkyl methacrylates having 1 to 6 carbon atoms in ether radicals such as ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, tert- butyl methacrylate, pentyl methacrylate, isopentyl methacrylate, hexyl methacrylate, 2,2-dimethyl butyl methacrylate, cyclopentyl methacrylate, cyclohexyl methacrylate, and methyl methacrylate, for example, is particularly preferred.

Monomers (m2) are selected from the group of vinyl aromatic compounds, such as α-halogen styrene, p-methyl styrene, p-tert-butyl styrene, vinyl naphthalene, and preferably α-methyl styrene, and particularly preferably styrene.

Maleic anhydride monomer (m3) is used with a purity of at least 95%, preferably at least 99%. In order to convert maleic anhydride to a liquid state of aggregation, it is heated above its melting point of 52.85 ° C, preferably to temperatures between 55 and 80 ° C, more preferably between 60 and 80 ° C. At the temperatures indicated above, liquid maleic anhydride can be stored in an inert gas atmosphere for many weeks.

Alkyl acrylates (m4) can be included in a fraction of up to 5% by weight in order to improve the rheological properties of the TC triple copolymers. Examples of alkyl acrylates having from 1 to 6 carbon atoms in the ester radical are ethyl acrylate, isopropyl acrylate, propyl acrylate, isobutyl acrylate, tert-butyl acrylate, pentyl acrylate, hexyl acrylate, and preferably butyl acrylate, and particularly preferably methyl acrylate.

The monomers (m1), (m2) and (m4) and mixtures thereof are liquid under mixing conditions.

The corresponding copolymers can be obtained in the usual way of radical polymerization. European patent application EP-A 264590 describes, for example, a method for producing an injection compound from a mixture of monomers, including methyl methacrylate, vinyl aromatic compound, maleic anhydride and, if desired, lower alkyl acrylate, the polymerization being carried out to a conversion of 50% in the presence or absence of not polymerizable organic solvent and continue polymerization above the conversion of at least 50% in the temperature range from 75 to 150 ° C in the presence of an organic solvent until the conversion of at least 80%, and then sparyayut low molecular weight volatiles.

Japanese application JP-A 60-147417 describes a method for producing high heat-resistant polymethacrylate injection compounds, in which a mixture of monomers from methyl methacrylate, maleic anhydride and at least one vinyl aromatic compound is fed at a temperature of from 100 to 180 ° C. to a polymerization reactor suitable for polymerization in solution or in bulk, and polymerization is carried out. German patent application DE-A 4440219 describes a further manufacturing process.

Suitable binders include those poly (meth) -acrylate compounds which, for example, consist of from 90 to 100% by weight of methyl methacrylate units and which, due to the specific preparation process, reach Vick VST softening points (ISO 306 V) of at least 115 ° C, preferably from 116 to 122 ° C. European patent application EP-A 245647 describes, for example, a method for producing injection-molded poly (meth) -acrylate compounds by emulsion polymerization at polymerization temperatures from 0 to 100 ° C, for example, from 20 to 90 ° C, in the presence of an initiator and a regulator in a ratio of at least 1: 2, preferably 1: 5 or higher. Injection poly- (meth) -acrylate compounds thus obtained have a tact fraction of syndiotactic triads of more than 60%, while an isotactic fraction is preferably less than 5%. The temperature of the destruction of the casting composition (depolymerization of 2% at a heating rate of 5 ° C / min) is preferably at least 290 ° C. Vicat softening points VST (ISO 306 V) range from 115 to 122 ° C. Accordingly, the resulting polymers can consist of from 90 to 100% by weight of methyl methacrylate units. In a proportion of from 0 to 10%, preferably from 0 to 5%, in particular from 0 to 2% by weight, it is possible, where appropriate, the presence of freely radical polymerizable comonomers, such as, for example, methyl acrylate, ethyl acrylate, methacrylonitrile, maleic acid, maleic anhydride, methacrylic esters or methacrylamides, styrene, p-methyl styrene, vinyl esters or vinyl amides.

The following method of producing poly (meth) -acrylate compounds, which consist, for example, from 90 to 100% by weight of methyl methacrylate units and achieve Vick softening points VST (ISO 306 V) of at least 115 ° C., is known as "anionic polymerization" in the presence of complex catalysts (see, for example, Elias HG (1996): Polymere; Von Monomeren und Makromolekulenzu Werkstoffen, Hüthig & Wepf). This method, however, is very complex, and to date has not actually been used in practice.

As a binder, in addition, it is possible to use a poly- (meth) -acrylimide compound obtained by partial or complete imidation of polymers of methacrylic acid alkyl esters by reaction with an imidating agent (see, for example, European patent applications EP-A 441148 or EP-A 666161). Preference is given to poly- (meth) -acrylimide compounds having an imidation degree (glutarimide content) of from 50 to 100%, preferably from 60 to 95%, in particular from 65 to 80% by weight. For imidization degrees below 100%, poly- (meth) -acrylimide compounds typically include other comonomers, such as methacrylic acid and methacrylic anhydride, as by-products of the imidation process, for example, in each case, from 1 to 15% by weight,

Methods for preparing said polymethacrylimides are known from European patent applications EP-A 216505, EP-A 666161 or from European patent application EP-A 776910.

Solvents

Suitable solvents are halogenated or, preferably, halogen-free aliphatic, cycloaliphatic and aromatic hydrocarbons, ketones, esters, ethers, alcohols or phenols in which these binders are readily soluble.

Examples of suitable solvents include toluene, xylene, tetrahydrofuran, ketones such as acetone, methyl isobutyl ketone, isophorone, butanone, methyl ethyl ketone, esters such as methyl acetate, ethyl acetate, butyl acetate, butyl propionate, methoxypropyl acetate, alcohols such as methanol or methanol halogenated hydrocarbons like chloroform, methylene chloride and chlorobenzene.

Mixtures of methyl ethyl ketone and alcohols, for example ethanol, isopropanol and / or butanol, are suitable, for example.

Mixtures of xylene, methyl ethyl ketone, butyl acetate, ethoxylated alcohols, for example ethoxybutanol and / or methoxybutyl acetate (Butoxyl®), are preferred, the mixtures may include, where appropriate, minor proportions of solvent solvent-naphtha (technical benzene or heavy benzene, mixtures from 50 to 70% cumene, 30 to 40% xylene and 2 to 7% naphthalene oil.

Particular preference is given to mixtures of two to three parts by weight of xylene, approximately one part by weight of methyl ethyl ketone, approximately one part by weight of butyl acetate, approximately one part by weight of ethoxylated alcohol, for example ethoxybutanol and one part by weight of methoxybutyl acetate (Butoxyl® ) and about half of the solvent solvent naphtha by weight (technical benzene or heavy benzene, a mixture of Chemical Abstracts from 60% cumene, 35% xylene and 5% naphthalene oil).

Excipients

The paint may, where appropriate, include conventional excipients, preferably in an amount up to 15% by weight, in particular from 0.1 to 10% by weight. Examples of common adjuvants used in paints include dye activators or UV stabilizers and / or UV absorbers, fillers, if desired, moisturizing agents and preservatives.

The improved stability of the coating according to the invention to atmospheric factors is achieved by incorporating UV stabilizers, such as those known as polymer additives and listed in (Ullmanns Enzyklopedie der technischen Chemie, 4th Edition, Volume 15, pages 253 to 260, and / or successfully using polymerizable UV stabilizers. As an example of polymerizable UV stabilizers, 3- (2-benzotriazolyl) -2-hydroxy-5-tert-octylbenzylmethacrylamide may be mentioned UV absorbers may be present, for example, in amounts of from 0.1 to 10 % the mass of ink particles relatively hard.

Pressed casting / process

In the process of producing pressed castings, films of transparent and translucent polymers are used, printed on the back side with screen printing ink. The printed films are formed and, in an injection molding machine, reinforced on the reverse side by injection molding from the inside with thermoplastics, to obtain relatively thick pressed moldings.

Film

Films that are suitable for back-side printing can be obtained, for example, from thermoplastics, preferably transparent thermoplastics, such as polystyrene, polycarbonate, polyethylene terephthalate or polymethyl methacrylate, for example, preferably impact-resistant polymethyl methacrylate. Suitable, for example, poly (meth) acrylates, consisting of from 80 to 99.9% by weight of methyl methacrylate and from 0.1 to 20% by weight of other comonomers. Examples of suitable comonomers include methacrylic acid esters (e.g. ethyl methacrylate, butyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate), acrylic esters (e.g. methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, cyclohexyl acrylate) such as styrene and methyl styrene or p-methyl styrene.

Impact modifiers for polymethacrylate polymers are well known. As impact modifiers for poly (meth) acrylates, you can use cross-linked single-layer or multilayer emulsion polymers, consisting of, for example, cross-linked polybutyl acetate. The preparation and structure of impact-resistant polymethacrylate molding compositions are described, for example, in European patent applications EP-A 0113924, EP-A 0522351, EP-A 04655049 and EP-A 0683028.

The film thickness may be, for example, from 10 to 500 microns, preferably from 50 to 300 microns. The printed film is an intermediate product for the respective molded castings.

Typing operation

Films are printed in the usual way in the process of screen printing (see, for example: E. Schulz. Ein lehrreiches Fachseminar in Stuttgart: Bedrucken von Kunststoffen, Verpackungs-Rundschau 11/1985, pp. 1262-1270 or W. Krause "Siebdruck aufenststenstenstenstenstenstenstenstenstenstenstenenstunstckenfenstckenfenstckenfenstckenfenstckenfenstckenfenstckenfenstckenfenstck ", Plastverarbeiter, No.9, 1981, pp. 1249-1251).

Inside-out injection process / process

The process of obtaining molded castings includes the following stages,

but. Thermoplastic film printing in the process of screen printing with ink,

b. Forming a film, for example, by a high-pressure molding process. In this process, the film is installed in a holder, for example in a mounting device, and formed at a temperature that can lie between room temperature, i.e., from about 20 ° C, and a temperature below the Vicat softening temperature (VST, as defined in ISO 306, procedure B), under pressure, by means of, for example, compressed air at a pressure of, for example, from 50 to 300 bar. A process of this type is known, for example, from European patent application EP-A 0371425.

at. Injection molding from the inside out on the printed film from the printed side in a thermoplastic injection mold, and

g. Removing the pressed cast from the mold.

The printed films are placed in an injection mold so that the printed one faces the nozzle side and is injection molded from the inside with a thermoplastic layer with a thickness of, for example, 0.5 to 10 mm, preferably 0.5 to 2 mm. You can use, for example, an injection mold with heated runners with a needle gate valve. Examples of thermoplastics suitable for injection molding from the inside out include polycarbonate, mixtures of polycarbonate and a copolymer of acrylonitrile, butadiene and styrene (ABS), block copolymers of acrylonitrile-styrene-acrylonitrile (ACA), and preferably polymethylmethacrylate.

Suitable, for example, poly (meth) acrylates, consisting of from 80 to 99.9% by weight of methyl methacrylate and from 0.1 to 20% by weight of other comonomers. Examples of suitable comonomers include, for example, methacrylic acid esters (e.g. ethyl methacrylate, butyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate), acrylic acid esters (e.g. methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, cyclohexyl acrylate, such as methyl styrene or p-methyl styrene.

Particular preference is given to polymethyl methacrylates, which are copolymers from 98 to 95% by weight of methyl methacrylate and from 2 to 5% by weight of methyl acrylate, having an average molecular weight (weight average; measured by thin-layer chromatography or determined by GPC) in the range from 100,000 to 200,000, preferably from 100,000 to 130,000. Of the particularly suitable, for example, an injection composition which is a copolymer of 97% by weight of methyl methacrylate and 3% by weight of methyl acrylate and has an average molecular weight of approximately 110,000.

Suitable injection mold temperatures range from 40 to 80 ° C, preferably from 55 to 65 ° C. The melt temperature, especially in the case of a polymethyl methacrylate copolymer, can be in the range from 220 to 300 ° C., preferably from 240 to 260 ° C. The temperature of the heated molds may be in the range from 220 to 300 ° C., preferably from 240 to 260 ° C. The injection speed can vary from low to high.

Pressed Castings

After the injection molding operation has been completed from the inside, the cooled pressed molding can be removed from the injection mold.

The molded molding according to the invention consists of a thermoplastic film, preferably a transparent thermoplastic, in particular a polymethyl methacrylate copolymer film on which the ink according to the invention is printed on the back and which is provided on this side with a thermoplastic coating layer, which, preferably , represents polymethylmethacrylate, and the specified layer is deposited by injection molding from the inside.

Use

Pressed castings in accordance with the invention can find numerous applications: for example, as instrument covers - covers, for example, for electronic devices, mobile phones (cell phones), backlit displays, for example, for tools or, for example, as color lamps, for example, indicator lamps or discharge lamps, for example, in motor vehicles, rail transport or aviation.

Advantageous Effects of this Invention

The paint according to the invention has the advantage that it is resistant to high pressures and temperatures during the injection molding operation from the inside in order to produce molded moldings. In addition, even after a long period of use of the pressed castings, the printed image does not show any noticeable discoloration or yellowing. Pressed castings in accordance with the invention, especially if the material of the outer films and / or the back-cast coating is a polymethyl methacrylate copolymer, are remarkable for their high transparency and atmospheric stability. Pressed castings obtained in accordance with this invention therefore satisfy stringent quality requirements, such as those imposed, for example, on backlit displays or lamps for automobiles or aircraft.

Examples

Conventional commercial films of impact-resistant polymethylmethacrylate were printed on one side with various screen printing inks (inks 1 to 3), and then polymethylmethacrylate polymer was cast from the inside out on the printed side and reinforced so as to obtain pressed castings (test items). The test items were then tested for printing removal by rinsing.

The thickness of the films used was 250 μm. Films were molded under pressure from the inside with (MT) and without (OT) drying before screen printing.

Paint 1 (in accordance with the invention):

Paint 1 consists of a mixture of solvents, including

40% by volume of xylene,

17% by volume of methyl ethyl ketone,

17% by volume of methoxybutyl acetate (Butoxyl®)

17% by volume of butyl acetate and

9% by volume of solvent naphtha

(technical benzene or heavy benzene, a mixture of approximately 60% cumene, 35% xylene and 5% naphthalene oil), and contains relatively wet paint 10% by weight of carbon black pigment and 20% by weight of a binder, which is a 65% copolymer by weight of methyl methacrylate, 20% by weight of styrene and 15% by weight of maleic anhydride. The Vicat softening temperature of the binder, VST, as defined in ISO 306 V, lies in the range from 119 to 123 ° C.

Paint 2 (in accordance with the invention):

The composition corresponds to the paint 1 with the difference that the binder is present in the form of a copolymer of polymethacrylimide consisting of polymethyl methacrylate with a degree of imidization of approximately 70%. The copolymer also includes from about 4 to 6% by weight of methacrylic acid and from about 4 to 6% by weight of methacrylic anhydride as comonomers. The Vicat softening temperature of the binder, VST, as defined in ISO 306 V, lies in the range from 143 to 152 ° C.

Paint 3 (comparative experiment)

The composition corresponds to the paint 1 with the difference that the binder used is a regular commercial polycarbonate.

The conditions of the experiment.

An injection mold with heated runners with a gate valve was used. The cavity had dimensions of 100 × 100 mm with four different steps of height 1, 2, 3 and 4 mm (step plate).

Printed films were cut to size and placed in an injection mold so that the print points were directed toward the nozzle.

Injection molding from the inside was carried out under four different conditions from A to G, where A represents the most stringent requirement for screen printing stability, and G the least stringent one.

Injection molding from the inside was carried out by an injection compound consisting of polymethyl methacrylate (a copolymer of 97% by weight of methyl methacrylate and 3% by weight of methyl acrylate with an average molecular weight of approximately 110,000, measured by thin-layer chromatography or determined by GPC) (see table 1) .

Table 1 Experiment Condition Melt temperature (° C) Mold temperature (° C) The temperature of the heated runner (° C) Injection speed BUT 260 60 265 low B 260 60 265 high AT 280 60 280 high R 280 60 280 low

High injection rate = 100% of the possible installation capacity.

Low injection rate = approximately 25% of the possible plant capacity.

Pressed castings were removed from the mold and the screen printing wash was evaluated, in each case visually, using an evaluation system to remove the printed image by washing.

Grade ++: no noticeable leaching

Grade +: virtually no noticeable leaching

Assessment -: distinct washout

A number of experiments and their results are shown in table 2.

table 2 Experiment Conditions BUT B AT R Paint 1 (MT) ++ ++ + + Paint 1 (FROM) ++ + + + Paint 2 (MT) ++ ++ + + Paint 2 (FROM) ++ + + + Paint 3 (MT) + + + -

MT = printed films were dried at 80 ° C for 30 minutes before the operation of injection molding from the inside.

FROM = printed films were not dried before the injection molding operation from the inside out.

Claims (6)

1. Ink suitable for printing on transparent thermoplastic films, consisting mainly of a) one or more pigments, b) a binder in solution, c) an organic solvent or a mixture of organic solvents, d) conventional excipients, if desired, characterized in that as the binder use a copolymer of poly- (meth) -acrylate containing (m1) from 50 to 90% by weight of alkyl methacrylate having from 1 to 6 carbon atoms in the ether radical, (m2) from 5 to 25% by weight of at least one vinyl aromatic compound, (m3) from 1 to 25% by weight of maleic anhydride and, if desired, (m4) from 0 to 5% by weight of an alkyl acrylate having from 1 to 6 carbon atoms in an ether radical; or a copolymer of poly (meth) acrylimide containing polymethyl methacrylate with a degree of imidation of from 65 to 80%, from 1 to 15 wt.% methacrylic acid and from 1 to 15 wt.% methacrylic anhydride, wherein said copolymer has a Vicat softening point (ISO 306 V) of at least 115 ° C. 2. The paint according to claim 1, characterized in that the solvents used are aliphatic, cycloaliphatic and aromatic hydrocarbons, ketones, esters, ethers, alcohols, phenols or mixtures thereof. 3. A film of thermoplastic, characterized in that it is imprinted with ink according to claim 1 or 2. 4. A pressed casting consisting of a thermoplastic film printed on the back side with ink according to claim 1 or 2, and provided with a thermoplastic coating layer on this side, said layer being applied by injection molding from the inside out. 5. The pressed casting according to claim 4, characterized in that the film and / or plastic for the injection molding operation from the inside is a copolymer of polymethyl methacrylate. 6. Method for the production of molded castings, characterized by stages a) printing a film of thermoplastic by the process of screen printing with ink according to claim 1 or 2, and b) film forming, c) injection molding from the inside out on the printed film from the printed side in the injection mold by thermoplastic and g) removing the pressed cast from the mold.